The Ketoglutaric acid reference article from the English Wikipedia on 24-Apr-2004
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Ketoglutaric acid

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Ketoglutaric acid is used for either of two crystalline keto derivatives C5H6O5 of glutaric acid. As alpha-Ketoglutaric acid (2-Oxo-1,5-pentanedioic acid) a Krebs cycle intermediate.

It is sold in dietary supplements and to body builders as AKG.